This invention relates to the treatment of metal surfaces to increase resistance to corrosion. In another aspect this invention relates to compositions which form a corrosion resistant film on metal surfaces to which the compositions are applied. This invention further relates to the inhibition of corrosion caused by compositions comprising acidic liquids in contact with metal during acidic processing, e.g. pickling. More particularly, the invention relates to inhibiting such corrosion by adding to the composition an additive which will impart the desired properties thereto.
The problem of corrosion of metal surfaces in contact with various corrosive materials is well known. Most acidic liquids or compositions comprising same will cause corrosion when in contact with metals. The extent of such corrosion will, of course, depend to a large extent on the system on or in which the acidic material is to be used or upon the environmental conditions of such use. For example, corrosion of metal pipes, pumps and other equipment is a serious problem requiring monitoring of metal surfaces in drilling equipment used in oil well recovery operations. The down well metal surfaces are in contact with large quantities of corrosive materials and extreme conditions of temperature and pressure act to accelerate corrosion and intensify the problems of maintaining chemical protection for the equipment.
Conventional corrosion inhibiting agents are often not effective at all under extreme conditions or reduce corrosion for only a short period of time and then must be reapplied often at great expense and inconvenience if the well site is not easily accessible or poses difficulties of transporting and applying large volumes of chemicals.
In the area of coating of metals, a clean surface is a prerequisite to a quality coating. Grease, metal oxides, including scale, shop dirt, will adversely affect the adhesion, continuity and permanence of the coating by acting as a physical barrier which prevents proper bonding of the coating to the metal.
Metal surfaces can be cleaned by solvent, solvent emulsion, alkaline cleaners, solvent vapor degreasing, or abrasive blasting. Conventional cleaners will not remove scale and oxides from metals. Thus, it is necessary sometimes to use an acid treatment (pickling) to remove rust and other corrosion products. However, acids generally used are corrosive and, therefore, there is a need to inhibit such corrosion.
The invention relates to methods and materials suitable for inhibiting corrosion of a material subject thereto and particularly concerning the inhibition of corrosion of metals such as porous metal, aluminum, copper, brass, solder, and the like.
Accordingly, an object of this invention is to provide compositions which can be applied to metal surfaces to inhibit corrosion and pitting of the metal.
Another object of the invention is to provide a method of treating metal surfaces so as to form a film which inhibits corrosion on the metal even under extreme conditions of temperature and pressure and in highly corrosive environments.
Onother object of this invention is to provide inhibitors effective for decreasing corrosion due to acidic materials.
Other objects, aspects, as well as the several advantages of the invention will be apparent to those skilled in the art upon reading the specification and the appended claims.